When scientists exploring the Amazon River stumble on a “missing link” connecting humans and fish, they plan to capture it for later study. But the Creature has plans of his own, and has set his sights on the lead scientist's beautiful fiancée, Kay.

Richard Carlsonas Dr. David Reed
Julie Adamsas Kay Lawrence
Richard Denningas Dr. Mark Williams
Antonio Morenoas Dr. Carl Maia
Nestor Paivaas Captain Lucas
Whit Bissellas Dr. Edwin Thompson
Bernie Gozieras Zee
Ricou Browningas The Gill Man In Water (uncredited)
Art Gilmoreas Narrator (voice) (uncredited)